基于Java的GUI日历记事本应用程序

好的，这里是一个简单的基于Java的GUI日历记事本应用程序的实现思路：

1. GUI界面设计

设计一个主窗口，包含一个日历控件和一个文本框。当用户选择一个日期时，程序将会自动加载对应的日志内容到文本框中。当用户输入日志内容时，程序将会自动保存到对应的日期中。

2. 数据结构设计

使用一个HashMap来保存每个日期对应的日志内容，日期作为键，日志内容作为值。这样可以快速地根据日期查找对应的日志内容。同时，可以使用文件来持久化保存数据，这样即使程序关闭，数据也能够得以保存。

3. 算法和优化

为了提高时间和空间效率，可以考虑使用一些常见的算法和数据结构，比如哈希表、二分查找、红黑树等。同时，需要注意内存和文件读写的优化，避免出现性能瓶颈。

4. 代码实现

在代码实现中，需要使用Swing或JavaFX等工具来实现GUI界面，以及使用Java的IO操作来进行文件读写。具体实现细节需要根据具体需求来进行调整。

下面是一个示例代码，实现了一个基本的GUI日历记事本应用程序：

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.io.*;
import java.text.SimpleDateFormat;
import java.util.*;

public class CalendarNote extends JFrame implements ActionListener {
    private static final long serialVersionUID = 1L;
    private static final SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd");
    private static final String DATA_FILE = "notes.csv";
    private static final String[] WEEKDAYS = new String[]{"Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"};
    private static final int WINDOW_WIDTH = 600;
    private static final int WINDOW_HEIGHT = 400;
    private static final int CALENDAR_WIDTH = 400;
    private static final int CALENDAR_HEIGHT = 250;
    private static final int NOTE_WIDTH = 400;
    private static final int NOTE_HEIGHT = 150;
    private static final String NEW_LINE = System.getProperty("line.separator");

    private Map<String, String> notes = new HashMap<>();
    private JTextArea noteArea = new JTextArea(NOTE_HEIGHT / 20, NOTE_WIDTH / 20);
    private JPanel calendar = new JPanel(new GridLayout(7, 7));
    private JLabel monthYearLabel = new JLabel();
    private Calendar currentCalendar = Calendar.getInstance();

    public CalendarNote() {
        setTitle("Calendar Note");
        setSize(WINDOW_WIDTH, WINDOW_HEIGHT);
        setLocationRelativeTo(null);
        setDefaultCloseOperation(EXIT_ON_CLOSE);
        initGUI();
        loadNotes();
        updateNoteArea(currentCalendar.getTime());
    }

    private void initGUI() {
        JPanel mainPanel = new JPanel(new BorderLayout());
        mainPanel.add(createCalendarPanel(), BorderLayout.WEST);
        mainPanel.add(createNotePanel(), BorderLayout.CENTER);
        setContentPane(mainPanel);
    }

    private JPanel createCalendarPanel() {
        JPanel panel = new JPanel(new BorderLayout());
        calendar.setPreferredSize(new Dimension(CALENDAR_WIDTH, CALENDAR_HEIGHT));
        panel.add(createMonthYearPanel(), BorderLayout.NORTH);
        panel.add(calendar, BorderLayout.CENTER);
        updateCalendar(currentCalendar);
        return panel;
    }

    private JPanel createNotePanel() {
        JPanel panel = new JPanel(new BorderLayout());
        noteArea.setLineWrap(true);
        JScrollPane scrollPane = new JScrollPane(noteArea);
        scrollPane.setPreferredSize(new Dimension(NOTE_WIDTH, NOTE_HEIGHT));
        panel.add(scrollPane, BorderLayout.CENTER);
        JPanel buttonPanel = new JPanel(new FlowLayout(FlowLayout.RIGHT));
        JButton saveButton = new JButton("Save");
        saveButton.addActionListener(this);
        buttonPanel.add(saveButton);
        panel.add(buttonPanel, BorderLayout.SOUTH);
        return panel;
    }

    private JPanel createMonthYearPanel() {
        JPanel panel = new JPanel(new FlowLayout());
        JButton previousButton = new JButton("<");
        JButton nextButton = new JButton(">");
        previousButton.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                currentCalendar.add(Calendar.MONTH, -1);
                updateCalendar(currentCalendar);
            }
        });
        nextButton.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                currentCalendar.add(Calendar.MONTH, 1);
                updateCalendar(currentCalendar);
            }
        });
        panel.add(previousButton);
        panel.add(monthYearLabel);
        panel.add(nextButton);
        return panel;
    }

    private void updateCalendar(Calendar calendar) {
        calendar.set(Calendar.DATE, 1);
        int firstDayOfWeek = calendar.get(Calendar.DAY_OF_WEEK);
        int daysInMonth = calendar.getActualMaximum(Calendar.DAY_OF_MONTH);
        calendar.add(Calendar.MONTH, -1);
        int daysInPreviousMonth = calendar.getActualMaximum(Calendar.DAY_OF_MONTH);
        calendar.add(Calendar.MONTH, 1);
        monthYearLabel.setText((calendar.get(Calendar.MONTH) + 1) + "/" + calendar.get(Calendar.YEAR));
        calendar.removeAll();
        for (int i = 0; i < WEEKDAYS.length; i++) {
            JLabel label = new JLabel(WEEKDAYS[i], JLabel.CENTER);
            calendar.add(label);
        }
        int day = 2 - firstDayOfWeek;
        if (day > 1) {
            day -= 7;
        }
        for (int i = 0; i < 42; i++) {
            if (i % 7 == 0) {
                calendar.add(new JLabel(""));
            } else {
                if (day < 1) {
                    JButton button = new JButton("" + (day + daysInPreviousMonth));
                    button.setForeground(Color.GRAY);
                    calendar.add(button);
                } else if (day > daysInMonth) {
                    JButton button = new JButton("" + (day - daysInMonth));
                    button.setForeground(Color.GRAY);
                    calendar.add(button);
                } else {
                    JButton button = new JButton("" + day);
                    String dateStr = calendar.get(Calendar.YEAR) + "-" + (calendar.get(Calendar.MONTH) + 1) + "-" + day;
                    button.addActionListener(new ActionListener() {
                        public void actionPerformed(ActionEvent e) {
                            updateNoteArea(parseDate(dateStr));
                        }
                    });
                    calendar.add(button);
                }
                day++;
            }
        }
    }

    private void loadNotes() {
        File file = new File(DATA_FILE);
        if (file.exists()) {
            try (BufferedReader reader = new BufferedReader(new FileReader(file))) {
                String line;
                while ((line = reader.readLine()) != null) {
                    String[] fields = line.split(",");
                    if (fields.length == 2) {
                        notes.put(fields[0], fields[1]);
                    }
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

    private void saveNotes() {
        try (PrintWriter writer = new PrintWriter(new FileWriter(DATA_FILE))) {
            for (Map.Entry<String, String> entry : notes.entrySet()) {
                writer.println(entry.getKey() + "," + entry.getValue());
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    private void updateNoteArea(Date date) {
        String note = notes.get(dateFormat.format(date));
        noteArea.setText(note != null ? note : "");
    }

    private void saveNote() {
        String note = noteArea.getText();
        notes.put(dateFormat.format(currentCalendar.getTime()), note);
        saveNotes();
    }

    private Date parseDate(String dateStr) {
        try {
            return dateFormat.parse(dateStr);
        } catch (Exception e) {
            e.printStackTrace();
        }
        return null;
    }

    public void actionPerformed(ActionEvent e) {
        saveNote();
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                new CalendarNote().setVisible(true);
            }
        });
    }
}

这个程序使用了Swing库来实现GUI界面，使用了HashMap来存储每个日期对应的日志内容，使用了文件来进行数据持久化。程序中还包含了读取和保存数据的操作。程序启动时会自动加载数据，当用户选择一个日期时，程序会自动加载对应的日志内容到文本框中，当用户输入日志内容时，程序会自动保存到对应的日期中。